Method of using lectins for contraception, prophylaxis against diseases transmittable by sexual contact, and therapy of such diseases, and apparatus for administering lectins

ABSTRACT

In order to prevent conception and/or the spread of sexually transmitted diseases (STD&#39;s) one or more lectins capable of binding sperm and/or the pathogenic microorganisms responsible for STD&#39;s are administered to the vagina prior to sexual intercourse. The lectins immobilize the sperm to render them incapable of fertilization and also bind to the microorganisms to render them non-pathogenic or to the cells to prevent infection by the microorganisms. Lectins can also be administered to treat sexually transmitted vaginal infections. The invention also encompasses a device for to be placed in the vault of the vagina which comprises a ring which surrounds the cervix and a membrane spanning the central aperture of the ring to prevent the direct contact of ejaculate with the cervical tissues. The device is impregnated or coated with lectins and releases them into the vaginal environment over a period of time.

RELATIONSHIP TO OTHER APPLCATIONS

This application is a continuation of application Ser. No. 09/156,696,filed Sep. 18, 1998, which is a continuation of application Ser. No.08/938,831, filed Sep. 26, 1997, now U.S. Pat. No. 5,840,771, which is acontinuation of application Ser. No. 08/759,517, filed Dec. 4, 1996,abandoned, which is a continuation of application Ser. No. 08/609,104,filed Feb. 29, 1996, abandoned, which is a continuation of applicationSer. No. 08/462,666, filed Jun. 5, 1995, abandoned, which is adivisional of application Ser. No. 08/317,599, filed Oct. 3, 1994,abandoned, which is a continuation-in-part of application Ser. No.08/130,190, filed Oct. 1, 1993, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to methods of contraception andprophylaxis against diseases transmittable by sexual contact and therapyof such diseases, and more particularly to a method using intravaginallyadministered lectins for contraception and to protect against thetransmission of diseases that are transmissible by sexual contact and totreat such diseases. The invention also relates to devices forintravaginal administration of lectins.

2. Brief Summary of the Prior Art

Sexually transmitted diseases (STD's) are epidemic in this country andworldwide. Furthermore, other diseases that have not traditionally beenconsidered to be STD's have also been found to be transmitted by sexualcontact, e.g., hepatitis B. The medical and public health problemsassociated with these epidemics have motivated a search for methods ofcontrolling these diseases by limiting their transmission from person toperson. Similarly, although many methods of contraception have beenemployed, no universally satisfactory method has been developed.

Hitherto it has been generally agreed that barrier methods which preventthe contact of body fluids between individuals are the most effectivemeans of preventing transmission of such diseases. Such barrier methodsare also effective contraceptive procedures. However, such methods aresomewhat inconvenient and require some cooperation between individuals.

An alternative method for preventing the transmission of sexuallytransmitted diseases is to kill the pathogenic microorganisms in semenand vaginal secretions so that they are incapable of invading thetissues and causing the disease. While intravaginally placedspermatocides have been used for contraception, alone or in combinationwith barrier methods, antimicrobial materials have not been so used toprevent STD's, probably because many of such materials are irritating toadjacent tissues.

Administration of biologically active materials to the vagina forwhatever purpose is usually accomplished by the use of some device thatprovides for convenient application of the medication by the userherself. A variety of devices exist for delivery of bioactive substancessuch as spermatocides and various medications. Each has its place in themedical armamentarium but each has certain deficiencies for applicationof contraceptive or anti-microbial agents in the context of sexualactivity. Conventional vaginal suppositories and ovules may not providemedication to the entire vagina because of their shape and placement bythe user in the vagina. Such suppositories are generally comprised of amaterial that melts at body temperature to allow the medication tospread and contact the tissues. However, when the dosage form melts, themedication may drain out of the vagina rather quickly, thus minimizingits potential effectiveness and significantly reducing the extendedexposure of the tissues and pathogens to the medication which is oftennecessary for effective treatment. Similarly, the effective duration ofcontraceptives applied in this way tends to be relatively brief. Inaddition, such delivery vehicles, even when freshly applied, do notprovide any physical barrier to deposition of male ejaculate on thecervix. Such ready access of sperm to the cervix may allow them toescape the action of spermatocides that are diffused throughout thevagina. Furthermore, because cells at the cervix are uniquely sensitiveto several pathogens such as Chlamydia trachomatis, the absence of abarrier deprives these cells of a significant means of protection.

In order to provide for a longer retention of medication in the vaginaand assure a more continuous delivery of active ingredients to thetissue, several types of vaginal rings have been proposed. Such devicesare disclosed, for example, in Duncan, U.S. Pat. No. 3,545,439; Roseman,U.S. Pat. No. 3,920,805; Schopflin, U.S. Pat. Nos. 4,012,496 and4,012,497; Wong et al., U.S. Pat. Nos. 4,237,885 and 4,286,587; and Nashet al., U.S. Pat. No. 4,292,965. The vaginal rings are generallyimpregnated with a spermatocide and are designed to be retained in thevaginal vault and to release the spermatocide slowly over a period oftime to maintain an effective contraceptive concentration of the activematerial in the vagina. However, such devices do not prevent the directcontact of ejaculate with the tissues of the cervix, and therefore donot protect those tissues from contact with pathogenic organisms whichmight be contained in the ejaculate. They are also of questionableefficacy in supplying the spermatocide where it is most needed.

Another approach is to use a cervical cap or a diaphragm to serve as amechanical barrier to the sperm and to dispense medication. Thesedevices are designed for a relatively tight fit either to the cervix orthe walls of the vagina to serve as a mechanical barrier to the passageof sperm. Such devices can be effective, especially as contraceptivesand when combined with spermatocides. However, because of the need toprovide a sperm-resistant seal they are frequently relatively complexdevices incorporating metallic springs within a rubber or syntheticresin structure to provide the required sealing force.

Another approach to providing an effective concentration of spermatocidein the vagina is to provide a sponge impregnated with a spermatocide.Such applicators are not intended to be precisely located and may permitthe contact of ejaculate with the tissues of the cervix, with theundesirable consequences outlined above.

Accordingly, a need has continued to exist for a method of contraceptionand prophylaxis against STD's by vaginal administration of aspermatocide and/or antimicrobial material, and for a simple andeffective device to protect the tissues at risk from contact withmicroorganisms while dispensing a spermatocidal and/or antimicrobialmaterial.

SUMMARY OF THE INVENTION

This need has now been alleviated by the method and device of thisinvention, according to which one or more lectins capable of bindingsperm and/or the pathogenic microorganisms responsible for STD's areadministered to the vagina or site of infection prior to sexualintercourse. The lectins immobilize sperm to render them incapable offertilization and also bind to the microorganisms to render themnon-pathogenic or to the cells to prevent infection by themicroorganisms.

The invention also encompasses a device for to be placed in the vault ofthe vagina which comprises a ring which surrounds the cervix and amembrane spanning the central aperture of the ring to prevent the directcontact of ejaculate with the cervical tissues. The device isimpregnated or coated with lectins and releases them into the vaginalenvironment over a period of time.

Accordingly, it is an object of the invention to provide an improvedmethod for prophylaxis against sexually transmitted diseases.

A further object is to provide a method of contraception.

A further object is to provide a method for binding and immobilizingpathogenic microorganisms in the vagina.

A further object is to provide a method for treating vaginal infections.

A further object is to provide a device for delivering lectins to thevagina over a period of time.

A further object is to provide an intravaginal device that protects thetissues of the cervix from direct contact with ejaculate.

Other objects of the invention will become apparent from the followingdetailed description when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a lectin-delivery device according to theinvention.

FIG. 2 is a bottom view of the lectin-delivering device of FIG. 1.

FIG. 3 is a cross section of the lectin-delivering device of FIGS. 1 and2, taken along the line 3—3.

FIG. 4 is a top plan view of another embodiment of the lectin-deliveringdevice of this invention.

FIG. 5 is a bottom view of the lectin-delivering device of FIG. 4.

FIG. 6 is a cross section of the lectin-delivering device of FIGS. 4 and5, taken along the line 6—6.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

Lectins are carbohydrate-binding proteins of nonimmune origin thatagglutinate cells or precipitate polysaccharides or glycoconjugates,i.e., proteins or lipids conjugated to oligo- or polysaccharides. Theyare widely distributed, and have been isolated from both plant andanimal sources. Their reactions with living cells are based on theirability to bind with antibody-like specificity to particulararrangements of the sugar residues that make up oligo- orpolysaccharides.

The surface of eucaryotic cells contain very numerous molecules ofglycoproteins and glycolipids. Similarly, the cell walls of bacteria andthe envelopes and capsids of viruses contain structural polysaccharidesand/or glycoproteins. The carbohydrate moieties of these molecules whichare displayed on the cell surfaces exhibit great variety in compositionand structure that serves to distinguish the types of cells and to serveas a signal to other cells or materials which come into contact with thecell. For, example, variation in the carbohydrate moieties ofglycoproteins in the membrane of red blood cells serves as the basis forthe conventional blood typing classification. When lectins recognize andbind to certain carbohydrate moieties they may serve to cross-link andagglutinate the cells bearing the binding groups, a property that earnsfor them the alternate name of agglutinins. Furthermore, because thesame sort of carbohydrate moieties often serve as attachment points forpathogens to bind to target cells and invade them, lectins may blockinfection of target cells by blocking the sites used by pathogens asrecognition markers. The same type of specific binding occurs betweensperm and egg in conception, and can be blocked by lectins. The bindingability of lectins may be very specific for certain mono- oroligosaccharides, allowing lectins to be used as a powerful tool forinvestigating the oligosaccharide epitopes on the surface of organismsor cells. Lectins can distinguish between blood cells of specific bloodtype, malignant from normal cells, and among species and genus oforganisms. While glycoproteins, glycolipids, and bacterial cell wallsare believed to be the main lectin-binding locations on the surface ofcells, it is not excluded that carbohydrate moieties derived from othermolecules or cellular structures may be displayed on the cell surface orthat other lectin-binding structures may be present on cell surfaces.All such lectin-binding structures may be targets for the lectins usedin the method of this invention.

Current medical uses of lectins include distinguishing erythrocytes ofdifferent blood types (blood typing). More recently, lectins have beenused ex-vivo in depleting T cells of patients undergoing bone marrowtransplantation.

In the context of this application the term microorganism includes anymicroscopic organism within the cataegories of algae, bacteria, fungi,protozoa, viruses, and subviral agents.

Among the microorganisms that are bound by certain lectins areinfectious organisms such as bacteria, protozoa, and viruses. Lectinsmay be used to identify such microorganisms in vitro and are alsocapable of binding to them in vivo, thereby preventing them frominfecting living cells. Human disease-causing organisms (and thediseases caused by them) that can be bound by lectins include Neisseriagonorrhoeae (gonorrhoea); Chlamydia trachomatis (chlamydia,lymphogranuloma venereum); Treponema pallidum (syphilis); Haemophilusducrei (chancroid); Donovania granulomatis (donovanosis); Mycoplasmapneumoniae, M. hominis, M. genitalium, Ureaplasma urealyticum(mycoplasmas); Shigella flexneri (shigella); Salmonella typhi, S.choleraesuis, S. enteritidis (salmonella); Campylobacter fetus, C.jejuni (campylobacter); human immunodeficiency virus HIV-1 and HIV-2(HIV, AIDS); HTLV-1 (T-lymphotrophic virus type 1); herpes simplex virustype 1 and type 2 (HSV-1 and HSV-2); Epstein-Barr virus;cytomegalovirus; human herpesvirus 6; varicella-zoster virus; humanpapillomaviruses (many types) (genital warts); molluscum contagiosum(MSV); hepatitis A virus, hepatitis B virus (viral hepatitis);Trichomoniasis vaginalis (trichomoniasis); yeasts such as Candidaalbicans (vulvovaginal candidiasis). Other diseases that are transmittedby contact with bodily fluids may also be transmissible by sexualcontact and are capable of being prevented by administration of lectinsaccording to this invention. Accordingly, the term sexually transmitteddiseases (STD's) is to be interpreted in this application as includingany disease that is capable of being transmitted in the course of sexualcontact, whether or not the genital organs are the site of the resultingpathology.

Inasmuch as lectins are also capable of agglutinating human sperm andother components of the male ejaculate, and thereby rendering the spermimmobile, intravaginal administration of lectins can also serve as amethod of contraception.

According to the invention a dose of lectins adapted to bind andagglutinate pathogenic microorganisms and/or block the recognition siteson target cells is administered to the vagina prior to sexualintercourse. The active ingredients may also include lectins capable ofbinding and/or inactivating sperm to serve as a contraceptive.

Because of the specificity of lectins for certain microorganisms, it ispreferred to administer a mixture of lectins chosen for their propertiesof agglutinating specific pathogens. It is also according to theinvention to administer a mixture of sperm-agglutinating lectins andlectins capable of binding to pathogenic organisms to providesimultaneous contraception and protection against infection.

A representative listing of lectins, the abbreviations by which they arereferred to, and their sources is given in Table 1.

TABLE 1 Lectins and Abbreviations Lectin Source AAnA Anguilla anguilla(Eel serum) AAurA Aleuria aurantia (Orange peel fungus) ABA Agaricusbisporus (Mushroom) ABrA Amphicarpanea bracteata (hog-peanut) ALHippaestrum hybrid (Amaryllis bulbs) APA Abrus precatorius (Jequiritybean) BPA Bauhinia purpurea alba (camel's foot tree) CAA Caraganaarborescens (Siberian pea tree) ConA Concanavalia ensiformis (Jack bean)CPA Cicer arietinum (chick pea) CSA Cytisus scoparius (Scotch broom) DBAColichos biflorus (horse gram) DSA Datura Stramonium (Jimson weed, Thornapple) ECA Erythrina crystagalli (Coral tree) ECorA Erythrinacoralldendron (Coral tree) EEA Euonymus europaeus (spindle tree) DBADolichos biflorus (horse gram) GNA Galanthus nivalis (Snowdrop bulb)GSA-1/GSA-lI Griffonia simplicifolia HAA Helix aspersa (Garden snail)HPA Helix pomatia (Roman or edible snail) JAC (Jacalin) Artocarpusintegrifolia (jackfruit) LAA Laburnum alpinum LBA Phaseolus lunatis(also limensis) (Lima bean) LCA (LcH) Lens culinaris (lentil) LEALycopersicon esculentum (Tomato) LOA Lathyrus oderatus (Sweet pea) LTA(LOTUS) Lotus tetragonolobus (Asparagus pea) MAA Maackla amurensis(maackla) MPA Maclura pomifera (Osage orange) NPL (NPA) Narcissuspseudonarcissus (daffodil) PAA Phytolacca americana (Pokeweed) PHA(PHA-L) Phaseolis vulgaris (Red kidney bean) PNA Arachis hypogaea(Peanut) PSA Pisum sativum (Pea) PWA Phytolacca americana (pokeweed)PTAgalactose Psophocarpus tetagonolobus (winged bean) PTAgalNacPsophocarpus tetagonolobus (winged bean) RCA-I/RCA-II Ricinus communis(Castor bean) RPA Robinia pseudoaccacia (black locust) SBA Glycine max(Soybean) SJA Sophora japonica (Japanese pagoda tree) STA Solanumtuberosum (Potato) TKA Trichosanthes kinlowii (China gourd) UEA-I/UEA-IlUlex europaeus (Gorse or Furz seeds) VAA Viscum album (Europeanmistletoe) VFA Vicia faba (Fava bean) VGA Vicia graminea VRA Vignaradiata (mung bean) VSA Vicia Sativa VVA Vicia villosa (Hairy vetch) WFAWisteria floribunda (Japanese wisteria) WGA Triticum vulgaris (Wheatgerm) suc-WGA Succinyl WGA

For example, N. gonorrheae is agglutinated by lectins that bind toN-acetyl-D-glucosamine residues on their surfaces. Such lectins includeWGA and STA, which are known to agglutinate all 193 clinical isolates ofN. gonorrheae. WGA is effective for such agglutination at aconcentration of 3.1 micrograms per milliliter. Other lectins showingsome agglutination activity with respect to N. gonorrheae include RCA-I,RCA-II, GSA-I, and SBA.

Certain species of Chlamydia (trachomatis, psittaci, and pneumoniae) areknown to be bound by the lectins ConA, DBA, UEA-1, SBA, and PNA. WGAalso binds to the receptors on certain cells, thereby blocking infectionby C. trachomatis and C. psittaci.

PHA binds to several isolates of H. ducrei, suggesting thatN-acetyl-D-glucosamine is present in the cell envelope polysaccharide.

WGA has been found to agglutinate a variety of bacterial cells,including Escherichia coli, Micrococcus luteus, and some types ofStaphylococcus aureus. WGA, specific for N-acetyl-D-glucosamine and SBA,specific for N-acetyl-D-galactosamine, are capable of agglutinating themany bacterial species which contain these sugar residues in their cellwall polysaccharides.

Various lectins are capable of binding to certain glycoproteins presentin the envelope of HIV virus. For example, ConA has been found to blockinfection of certain cell lines against infection by HIV in vitro, andconglutinin, a lectin derived from bovine serum, has been found to bindto the HIV envelope precursor protein gp 160, thereby preventingattachment to CD-4 receptors of target cells in vitro. GNA has beenfound to prevent infection of T-cells by HIV in vitro. Consequently,ConA, GNA and WGA have been found to be effective at preventinginfection of target cells by HIV-1 and HIV-2 in vitro. NPL andconglutinin have shown some activity as well.

HPA and ConA have demonstrated efficacy in the prevention of infectionof target cells by HSV-1 and HSV-2.

Lectins are also useful in aggregation of sperm. PHA, WGA, STA, ConA,PSA, APA, ECA, ECorA have demonstrated varying degrees of efficacy inagglutination of sperm.

While the lectins discussed above and the organisms against which theyare effective are representative of useful lectins according to theinvention, it is to be understood that other lectins may be discoveredwhich are active in the binding and agglutination of the pathogens ofsexually transmitted diseases, and that the use of such lectins isintended to be included within the scope of the invention.

In determining the amount of lectin to be administered for effectivebinding and/or agglutination of the pathogenic organisms of STD's, theamount of lectin that might be bound to vaginal tissues and thereby madeunavailable for agglutination of pathogens must be considered. Instudies on murine vaginal tissue, DBA, LAA, LBA, LCA, LTA, RCA-I,RCA-II, SJA, STA, VGA, WFA have been found not to bind to the tissue atany stage of the estrus cycle. In contrast, ABA, MPA, PHA-E, PHA-L, SucConA, and WGA bound strongly to vaginal tissues at all stages of theestrus cycle. CSA, GSA-I, GSA-II, HAA, HPA, JAC, PNA, PAA, SBA, Suc WGA,UEA-I, VFA, and VVA exhibited intermediate degrees of binding to murinevaginal tissues. The amount of lectin to be administered for effectiveprophylaxis can be determined from the relative binding effect of thevarious lectins to the pathogen and to the vaginal tissues.

The selection of particular lectins to be administered will depend onthe diseases sought to be prevented. It is preferred to administer amixture of lectins, each selected for best agglutinative efficacyagainst a particular pathogen.

The lectins may be administered in any fluid or ointment vehiclesuitable for topical administration of pharmaceutical compounds. Thuscreams, ointments, foams, suppositories, ovules and the like may beformulated in which the selected lectins are dispersed in a non-toxicvehicle suitable for topical and in particular for vaginaladministration. Such vehicles include white petrolatum, hydrophilicpetrolatum, lanolin emulsions, polyethylene glycols, cocoa butter andthe like. Useful vehicles include emollient oils such as water-solubleoils, e.g., liquid polyethylene glycols, which promote complete anduniform distribution of the medicament within the vagina. Representativesuitable vehicles include a lubricating jelly comprised of water,propylene glycol, hydroxyethyl cellulose, benzoic acid and sodiumhydroxide, a water-soluble oil comprised of water, glycerin, propyleneglycol, polyquaternium #5, methyl paraben and propyl paraben; a creamcomprised of benzyl alcohol, cetearyl alcohol, cetyl esters wax,octyldodecanol, polysorbate 60, purified water, and sorbitanmonostearate; and a suppository comprised of polyethylene glycol (PEG)18, PEG-32, PEG-20 stearate, benzethonium chloride, methyl paraben andlactic acid.

According to the invention, the dispersion, suspension, or solution oflectins in the vehicle may be applied to the site of a lesion on theexternal genitalia, such as the lesions produced by herpes simplex virustype 1 or type 2, chancroid, genital warts, chancre of syphilis, and thelike, to prevent the transfer of pathogens. The lectins may also beintroduced into the vagina in order to prevent conception or infectionby pathogens introduced during sexual intercourse. The amount of lectinsto be applied will be an amount that is effective to prevent conceptionor infection or substantially reduce the risk thereof. The amountsneeded to achieve these goals will depend on the effectiveness of theindividual lectins, their affinity for the target cell and the like. Theeffective amounts can be determined by the skilled practitioner byroutine experimentation.

Because of their ability to bind pathogenic micro-organisms, therebyinterfering with their mobility, growth and reproduction, lectins arealso useful in therapy of topical infections of the vagina. For thosediseases wherein the pathogens grow and reproduce within the lumen ofthe vagina, administration of lectins, alone or in combination withother antimicrobial materials, can assist in the treatment and cure ofthe infection.

Because some of the conventional means of administering medications tothe vagina have certain drawbacks, as discussed above, it is preferredto incorporate the lectins into a device which will remain in the vaginaand dispense the lectins over a prolonged period of time in order tomaintain an effective concentration of the lectins in the vagina. Such adevice may also be designed to provide a barrier that will prevent theaccess of pathogenic organisms into the uterus and may also function asa contraceptive device.

The device of the invention is generally a ring of elliptical orcircular cross-section made, e.g., from a biocompatible, nontoxicthermoplastic polymer or polymeric open-cell polyurethane. Bonded to oneside of the ring or molded integral with it is a web of the samematerial.

A device according to the invention having a ring of ellipticalcross-section is illustrated in FIGS. 1-3, wherein the referencenumerals indicate the same elements in each figure. A ring 102 ofgenerally elliptical cross section constitutes the main structuralmember of the device and is sized to fit comfortably in the vaginalvault surrounding the cervix. To one side of the ring 102 is fastened arelatively thin web 104, preferably made of the same material as thering. In some embodiments the web may be molded integrally with thering.

FIGS. 4-6 illustrate another embodiment of the invention wherein a ring202, of generally circular cross section, carries a thin web 204spanning the central aperture on one side of the ring.

The device may be manufactured from any material that has been shown tobe biocompatible with the environment of the vagina and to be capable ofholding lectins within its bulk and releasing them slowly to thesurrounding environment. Several materials suitable for this functionare already known from the vaginal devices already in use or disclosedin the technical literature. Consequently, the skilled practitioner caneasily select a suitable material from which to make the device of thisinvention. The lectins may also be incorporated into a thin flexiblecoating, placed on the ring or web or both, and designed to release thelectins therefrom over a period of time, e.g., by diffusion out of thecoating or by gradual erosion and dissolution of the coating in thevaginal environment.

The device of the invention is designed to deliver one or more lectinslocally in the vagina for:

1) contraception, by binding to the glycoproteins, glycolipids and otherglycoconjugates on the surface of sperm and by binding to theglycoproteins, glycolipids, and other glycoconjugates in the seminalfluid, thereby creating an ejaculate with significantly greaterviscosity, and thereby preventing sperm from exiting the ejaculate;

2) prophylaxis against various sexually transmitted diseases by bindingto the glycoproteins, glycolipids, and other glycoconjugates on thesurface of the bacterial agent or viral coat of the virus and theglycoproteins, glycolipids, and other glycoconjugates in the seminalfluid thereby preventing the infectious agent from reaching the targettissue;

3) prophylaxis against various sexually transmitted diseases by bindingto the glycoproteins, glycolipids and other glycoconjugate receptorsites on the vaginal stratified squamous epithelium and cervicalcolumnar epithelium, whereby the recognition sites for attack bypathogens are blocked or concealed; and

4) treatment of topical infections of the vagina by interfering with thegrowth and reproduction of the pathogenic microorganism, therebyhindering their ability to infect healthy cells.

The device of the invention also operates by providing a physicalbarrier to the direct deposition of ejaculate on the cervix. This designassures that the concentration of protective lectins in the cervicalregion will not be diluted and overwhelmed by the ejaculate. Rather, thesperm and the pathogens present in the ejaculate can only reach thecervical region gradually by diffusion and transport around the outsideof the peripheral ring of the device. This slow transport of the spermand pathogens from the ejaculate to the cervical region assures that thelectins will have an opportunity to bind to all appropriate constituentsof the ejaculate. The presence of the lectins, which will coagulate andinhibit the transport of sperm and pathogens, makes it unnecessary tohave a device that fits tightly either around the cervix or against thewall of the vagina.

Accordingly, the device of the invention has several advantages over thevaginal medication and contraceptive devices currently available:

1) It is easily inserted and comfortable to use.

2) Because of its position in the top of the vaginal canal, it ensuresthat the lectins are carried down through the vagina.

3) Since it is placed next to the cervix it can also deliver lectinstargeted to the cervix.

4) Gradual release of lectins provides a more consistent delivery overtime, thus ensuring more efficient treatment.

EXAMPLE 1

This example illustrates the utility of various lectins in binding tocertain microorganisms and to seminal plasma, sperm, human serum andcervical mucus.

The efficacy of binding of various lectins to human sperm and seminalplasma and cervical mucus, an indicator of the effectiveness of suchmaterials as vaginally-applied contraceptives, was investigated in vitroby the following procedures. Similarly the efficacy of lectin binding toNeisseria gonorrhoeae, the pathogen responsible for gonorrhoea, wasinvestigated by the following in vitro procedures. Such binding efficacyis an indication of the capability of such lectins to bind the pathogenand prevent infection when used intravaginally as a prophylacticmaterial.

Growth of bacteria: A cervical isolate of Chlamydia trachomatis serovarG ATCC VR-878 was grown in McCoy cell monolayers in the presence of 1 μgof cycloheximide per ml. The culture medium was 90% Eagle's minimumessential medium-10% fetal calf serum-10 mM HEPES (pH 7.3) supplementedwith 100 μg of vancomycin per ml. Elementary bodies were purified bydifferential centrifugation followed by density gradient centrifugationIn Percoll as described by Newhall et al. (Newhall, W. J., Baheiger, B.and Jones, R. B. 1982, Analysis of the human serological response to theproteins of Chlamydia trachomatis, Infection Immunity 38: 1181-1189).The purified elementary bodies were washed twice in 10 mM HEPES-145 mMNaCl (pH 7.4) and resuspended in bicarbonate buffer (100 mM NaHCO₃containing 0.01% NaN₃, pH 9.5). The density of elementary bodies wasadjusted to a McFarland No. 2 standard using the same buffer. Neisseriagonorrhoeae ATCC 19424 were grown on chocolate agar plates for 48-72 hrsat 37° C. in a CO₂ incubator (5% CO₂ and 80% humidity) and wereharvested by scraping bacteria from the agar surface and resuspendingthe cells in sterile phosphate buffered saline. The cells were washedthree times by centrifugation at 5000× g and resuspended in bicarbonatebuffer, the density of which was adjusted to a McFarland No. 2 standard(optical density as measured by a spectrometer—0.4 at 650 nm). The cellswere stored on ice prior to immediately testing in the lectin bindingassay. Lactobacillus jensenii ATCC 25258 was grown 48-72 hrs. at 37° C.in a shaking (incubator in MRS broth at pH 5.5 containing 2% glucose.After incubation, cells were centrifuged at 5000× g for 10 min andwashed twice in phosphate buffered saline, and the density was adjustedto a McFarland No. 2 standard with bicarbonate buffer. Haemophilusducreyi was grown on chocolate agar plates for 72 hrs in a CO₂ incubator(10% CO₂ and 80% humidity) t 31° C. Bacteria were harvested by scrapingbacteria from the agar surface and resuspending the cells in sterilephosphate buffered saline. The cells were washed three times bycentrifugation at 500× g, resuspended in bicarbonate buffer and the celldensity adjusted to a McFarland No. 2 standard. The cells were stored onice prior to immediately testing in the lectin binding assay.

Lectin Binding Assay: Biotinylated lectins were reconstituted inphosphate buffered saline (10 mM sodium phosphate-150 mM NaCl, pH 7.2)and stored in a freezer at −70° C. until used. Microtiter plates washedwith 95% ethanol and dried were coated with bacteria. (Chlamydiatrachomatis or Neisseria gonorrhoeae or Haemophilus ducryei orLactobacillus Jensenii) by adding 200 μl of a bacterial suspension (inbicarbonate buffer) to each well and incubating overnight at roomtemperature. Wells coated with bacteria were washed three times Ineither sodium acetate buffered saline, pH 4.0, containing 0.1% Tweendetergent (ABST) or phosphate buffered saline containing 0.1% Tween(PBST). Lectins defrosted at room temperature were diluted in eachbuffer, and 100 μl of various lectins was added to bacteria-coated wellsat a fInal concentration of 50 μg/ml. After incubation in a humidchamber at room temperature for 2 hours, wells were washed three timeswith either ABST or PBST followed by the addition to each well of 100 μlof alkaline phosphatase streptavidin (10 μg/ml). After incubation for 1hour at room temperature, wells were washed three times with ABST orPBST and 100 μl of freshly prepared p-nitrophenylphosphate (1 mg/ml) in0.1 M Tris buffer-0.15 M NaCl was added and color development wasquantified with a spectrophotometer at 405 nm.

Cervical Mucus: A sample of cervical mucus was obtained from a healthydonor and the gel phase separated by centrifugation. The pellet waswashed three times by centrifugation and the mucin stabilized andalkylated before dialysis against a low ionic strength, pH 8.0 buffer.The cervical mucus was bound to flat-bottomed plates by incubating inbicarbonate coating buffer at 4° C. overnight. The plates were washed toremove unbound ligand. Biotinylated lectins were serially diluted acrossthe plates in the wash buffer and the plates incubated at roomtemperature for 2 hrs. Unbound lectin was removed by washing, and thebound lectins were tagged by incubating with streptavidin-alkalinephosphatase at room temperature for 1 hr. Unbound streptavidin-alkalinephosphatase was removed by washing and the assay completed by addingfreshly prepared p-nitrophenylphosphate (1 mg/ml) in 0.1 M Trisbuffer-0.15 M NaCl) and monitoring the rate of color production.

Seminal Plasma and Sperm: A sample of ejaculate was donated by a healthydonor and the seminal plasma (supernatant) removed by centrifugation andfrozen at −20° C. The binding assay was performed in the same way as forcervical mucus.

The sperm pellet resulting from centrifugation of the ejaculate waswashed twice and total sperm count determined using a hemocytometer.Sperm were added to plates, left to settle at room temperature for 2hrs. and fixed using glutaraldehyde. The plates were then washed andunbound sites blocked with protein solution and stored at +4° C. untiluse. The remainder of the binding assay was performed in the same way asfor cervical mucus and seminal plasma.

Serum: A sample of blood was collected from a healthy donor, the serumseparated by centrifugation and stored at −20° C. The binding assay wasperformed in the same way as for cervical mucus and seminal fluid.

Analysis of data: Sigma Plot was used for graphing and curve fitting ofbinding plots. Velocity of the color-forming reaction versusconcentration of lectin added was plotted. Binding curves were fitted tothe hyperbolic equation f(x)=ax/(b+x) where “x” is the concentration oflectin, “f(x)” is the rate of reaction measured by change in opticaldensity (OD) of the reaction solution per unit time, “a” is theasymptotic value of maximum reaction velocity measured as change inoptical density per minute (represented in the following tables asm_(OD)/min) and “b” is the concentration of lectin where half of maximumbinding occurs (represented in the following tables as[Lectin]_(1/2 max)). The binding “quotient” is defined as a/b.

The data for lectin binding to sperm, seminal plasma, cervical mucus,human serum, Neisseria gonorrhoeae, and Lactobacillus jensenii aresummarized in the following tables.

TABLE 2 SUMMARY OF BINDING DATA QUOTIENT Seminal Cervical Human LectinSperm Plasma Mucus Serum ABA WB 0.44 WB WB AL NB NB NB NB BPA 0.60 0.8620.76 WB CAA 0.46 1.04 7.82 WB ConA 2.59 2.68 1.11 3.29 CPA WB WB WB WBCSA WB 0.30 7.30 WB DBA WB WB WB WB DSA 1.09 WB WB WB ECA WB WB WB WBEEA NB NB 0.39 NB GNA 0.36 0.58 0.24 WB GSA-I/GSA-II WB WB WB WB HAA NBWB WB WB Jacalin 3.43 11.63  21.55 8.93 LAA NB 0.57 WB WB LBA WB WB WBWB LcH 7.26 2.58 8.64 1.60 LES WB WB WB WB LOTUS NB 0.94 4.13 MAA NB WBWB NB MPA 2.29 3.17 13.8 1.18 NPA NB NB NB NB PWA WB NB NB NB PHA-L WBWB WB NB PNA WB WB 7.25 NB PSA 3.44 2.70 14.5 1.12 PTAgalactose NB WB1.31 WB PTAgalNacnb NB NB 1.39 WB RPA 1.28 0.84 0.45 WB SBA NB WB WB NBSJA NB WB WB NB STA NB WB WB NB sWGA 1.32 7.50 WB WB TKA WB 0.87 WB WBUEA-1 WB WB 14.72 WB VPA WB 2.78 5.21 2.02 VRA WB 3.35 WB WB VVA N/A0.81 WB WB WFA 2.48 1.96 26.24 WB WGA 19.38  4.87 12.77 1.13 Notes 1.N/A—not available 2. NB—no binding 3. WB—weak binding

TABLE 3 LECTIN BINDING TO SPERM Max [Lectin]_(1/2 Max) Lectin(m_(OD)/min) (μg/ml) Quotient WGA 155  8 19.38  LcH 196 27 7.26 PSA 14141 3.44 Jacalin 103 30 3.43 ConA  57 22 2.59 WFA  67 27 2.48 MPA  48 212.29 sWGA  41 31 1.32 RPA 120 94 1.28 DSA  63 58 1.09 BPA  67 112  0.60CAA  33 71 0.46 GNA  27 74 0.36

TABLE 4 LECTIN BINDING TO SEMINAL PLASMA Max [Lectin]_(1/2 Max) Lectin(m_(OD)/min) (μg/ml) Quotient Jacalin 93  8 11.63  sWGA 45  6 7.50 WGA112  23 4.87 VRA 208  62 3.35 MPA 57 18 3.17 VFA 125  45 2.7  PSA 100 37 2.70 ConA 51 19 2.68 LcH 147  57 2.58 WFA 49 25 1.96 CAA 51 49 1.04LOTUS 32 34 0.94 BPA 64 74 0.86 RPA 56 64 0.88 VVA 25 31 0.81 GNA 38 650.58 TKA 39 45 0.87 LAA 37 65 0.57 ADA 0.44 CSA 25 82 0.30

TABLE 5 LECTIN BINDING TO CERVICAL MUCUS Max [Lectin]_(1/2 Max) Lectin(m_(OD)/min) (μg/ml) Quotient WFA 656 25 26.24  Jacalin 237 11 21.55 BPA 353 17 20.76  UEA-1 265 18 14.72  PSA  58  4 14.50  MPA 138 1013.80  WGA 562 44 12.77  LcH 121 14 8.64 CAA 352 45 7.82 CSA 445 61 7.30PNA 174 24 7.25 VFA 203 39 5.21 LOTUS 194 47 4.13 PTAgalNac 110 79 1.39PTAgalactose 113 86 1.31 ConA  41 37 1.11 RPA  25 56 0.45 EEA  27 700.39 GNA  13 55 0.24

TABLE 6 LECTIN BINDING TO HUMAN SERUM Max [Lectin]_(1/2 Max) Lectin(m_(OD)/min) (μg/ml) Quotient Jacalin 134 15 8.93 ConA  79 24 3.29 VFA107 53 2.02 LcH 123 77 1.60 MPA  40 34 1.18 WGA 160 142  1.13 PSA  84 751.12

TABLE 7 LECTIN BINDING TO NEISSERIA GONORRHOEAE pH 4 Max[Lectin]_(1/2 Max) Lectin (m_(OD)/min) (μg/ml) Quotient BPA 1190  8214.51 CPA  80 33 2.42 CSA 560 7 80.00 GNA 294 18 16.33 LAA 176 42 4.19LBA 275 14 19.64 LCH 213 176 1.21 LEA 106 7 14.29 MAA 235 56 4.20 MPA159 5 31.80 NPA 299 38 7.87 PSA  55 13 4.23 RPA 233 10 23.30 SBA 414 851.75 STA 194 24 7.57 sWGA  49 0.50 90.00 TKA 178 55 3.24 VVA 411 3137.00 WFA 331 3 110.33 WGA 125 0.78 160.26

TABLE 8 LECTIN BINDING TO LACTOBACILLUS JENSENII Max [Lectin]_(1/2 Max)Lectin (m_(OD)/min) (μg/ml) Quotient ABA 216  2 108.00 BPA 557 57 9.77GNA 405 12 33.75 Jacalin 148  7 21.14 LBA 334 15 22.27 RPA 177 55 3.22SBA 523 63 8.30 WFA 464 23 20.17 STA 140 19 7.37 LEA  45 82 0.55 DSA  2680 0.33 MPA 2047  328  6.24 ConA 301  7 43.00 sWGA  96 64 1.50 LAA 13617 8.00 CSA 624 387  1.61 NPA 425 36 11.81 VVA 260 33 7.88

In the above tables the affinity of the lectin for a particularsubstrate is inversely proportional to the maximum velocity of thecolor-forming reaction. Consequently, those lectins having a smaller bvalue ([lectin]_(1/2 max)) bind more firmly to the substrate. A highbinding efficacy (low m_(OD)/min) is preferable for binding to sperm orseminal plasma for contraceptive purposes or to a pathogen, such asNeisseria gonorrhoeae, whose infections activity is to be inhibited.However, it must be recognized that some microorganisms of the vaginalflora, e.g., Lactobacillus jensenii, are desirable and may even providesome protection against pathogenic organisms. Accordingly, if possible,it is desirable to select a lectin for contraception and/or prophylaxisagainst sexually transmitted diseases that combines great bindingaffinity for the constituents of the male ejaculate or for a pathogenicmicroorganism, but has a lesser, preferably minimal, binding affinityfor beneficial vaginal flora. A skilled practitioner may select the mostefficacious lectins by consulting the data provided in the tables ofthis example.

EXAMPLE 2

This example illustrates the effectiveness of lectins in inhibiting theinfective activity of Chlamydia trachomatis.

Chlamydia trachomatis serovar G was cultured as described in Example 1.Lyophilized lectins were reconstituted in phosphate buffered saline(PBS) to a concentration of 1 mg/ml and frozen at −20° C. The lectinswere prepared for testing in the Chlamydia trachomatis inactivationassay by diluting them in McCoy growth medium (MEM) to appropriateconcentrations. Chlamydia trachomatis serovar G was added to the dilutedlectins and the mixture was incubated for 1 hour at 37° C. Afterincubation, the Chlamydia-lectin mixture was added to McCoy cells in15×45 mm shell vials and centrifuged at 3500× g for 60 minutes at 37° C.Following centrifugation, the medium in the vials was removed and 1 mlof Chlamydia overlay medium (with cycloheximide) was added to each vial.The vials were incubated for 42-43 hours and the cells were then fixedand stained for Chlamydia trachomatis using Syva Microtrak™ Chlamydiatrachomatis culture confirmation reagent.

Samples of the infected cell culture were then examined under themicroscope and evaluated for the effect of the lectin on the infectivityof the microorganism. Table 9 shows the number of Chlamydia trachomatisinclusions per 160× microscopic field on a 12 mm circular glasscoverslip as a percentage of a positive control sample which was notexposed to any lectins. WGA (118%) and ConA (121%) show enhancedinfectivity of Chlamydia trachomatis serovar G in having more inclusionsper 160× field than the positive control which had not been exposed toany lectins. In contrast, exposure to Jacalin shows significantlyreduced infectivity of Chlamydia trachomatis serovar G as evidenced bythe 65% reduction in the number of inclusions per 160× field (35% of thepositive control value).

TABLE 9 Lectin Concentration Infectivity ABA 150 59 TKA 150 80 WGA  50118  DSA  50 75 WFA 150 48 VFA 150 61 ConA 150 121  Jacalin 150 35 MPA150 55

EXAMPLE 3

This example illustrates the effectiveness of lectins in blocking theinfectivity of human immunodeficiency viruses Type 1 and 2(HIV-1/HIV-2).

The effect of lectins on the infectivity of HIV-1 and HIV-2 toward humanlymphocytes was investigated in vitro by a standard technique (Balzariniet al. 1991, Antimicrobial Agents and Chemotherapy, March 1991, pages410-416) wherein the toxicity of the lectins toward the infected cellswas determined (human T-lymphocytes CEM/0) and also the ability of thelectins to block the fusion of infected cells (HUT-78/HIV-1(III_(B)))with other cells (MOLT/4 clone 8). The results of these tests are setforth in Tables 10 and 11 below. The results are expressed in terms ofthe concentration of lectins required to reduce by 50% the number ofviable cells in the virus-infected cell cultures (EC₅₀) and in thecontrol cell cultures (mock-infected) (CC₅₀), respectively.

TABLE 10 Anti-HIV-1 and -HIV-2 Activity and cytotoxicity of Lectins inHuman T-Lymphocyte (CEM/0) Cells EC₅₀ ^(a) (μg/ml) CC₅₀ ^(b) CompoundHIV-1 HIV-2 (μg/ml) ABA >100 −> 100 >100 −> 100 83 − 62 >100 >100 73 ±15 CAA >100 −> 100 >100 −> 100 140 −> 200 >100 >100 ≧140 ConA 2.4 − 0.8− 1.4 1.8 − 0.8 − 2.4 20 − 19 1.5 ± 0.79 1.4 ± 0.77 20 ± 0.71 CPA >100−> 100 −> 100 >100 −> 100 −> 100 >200 −> 200 −> 200 >100 >100 >200CsA >100 −> 100 −> 100 >100 −> 100 −> 100 >200 −> 200 −>200 >100 >100 >200 DSA >20 >20 >10.5 ECA >100 −> 100 >100 −> 100 12 − 15≧100 ≧100 14 ± 2.5 EEA >0.16 −> 0.16 >0.16 −> 0.16 0.47 −0.53 >0.16 >0.16 0.50 ± 0.04 GSA-I >100 −> 100 >100 −> 100 >200 −>200 >100 >100 >200 GSA-II >100 −> 100 −> 100 >100 −> 100 −> 100 >90 −>200 −> 200 >100 >100 ≧90 HAA 20 − 9 11.5 − 11.5 9.7 − 18 15 ± 7.8 11.514 ± 5.9 JAC >20 −> 20 >20 −> 20 16 − 27 >20 >20 22 ± 7.4 LAA >100 −>100 >100 −> 100 >200 −> 200 >100 >100 >200 LBA >100 −> 100 >100 −>100 >200 −> 200 >100 >100 >200 LCH 9 − 4 − 20 >100 −> 100 −> 100 17 − 17− 12 11 ± 8.2 >100 15 ± 2.9 LEA >100 −> 100 >100 −> 100 >200 −>200 >100 >100 >200 Lotus >100 −> 100 >100 −> 100 90 −> 200 −>200 >100 >100 ≧90 MPA >0.8 −> 4 >0.8 −> 4 6.8 − 11 >0.8 >0.8 8.9 ± 3.0PAA >100 −> 100 >100 − 58 >200 −> 200 >100 ≧58 ≧140 PHA-L 11.5 − 11.5 −45 >100 −> 100 > 100 11 − 23 23 ± 19 >100 17 ± 8.5 PNA >100 −> 20 −>20 >100 −> 20 −> 20 95 − 80 >20 >20 88 ± 11 PSA 20 − 9 − 20 − 45 45 −100 − 100 25 − 17 16 ± 6.4 82 ± 32 21 ± 5.7 PTAgal >100 −> 100 −>100 >100 −> 100 −> 100 >200 −> 200 >100 >100 >200 PTAgalNac >100 −>100 >100 −> 100 >200 −> 200 >100 >100 >200 SJA >100 −> 100 >100 −>100 >200 −> 200 >100 >100 >200 sWGA >100 −> 100 >100 −> 100 >200 −>200 >100 >100 >200 TKA >100 −> 100 >100 −> 100 100 − 95 >100 >100 98 ±3.5 UEA-1 >100 −> 100 >100 −> 100 >200 −> 200 >100 >100 >200 VFA 9 − 34− 38 >100 −> 100 −> 100 120 − 77 − 95 34 ± 25 ≧100 97 ± 22 VVA >100 −>100 >100 −> 100 >200 −> 200 >100 >100 >200 WFA >100 −> 100 >100 −>100 >200 −> 200 >100 >100 >200 WGA 11.5 − 20 −> 20 9 −> 20 − 20 11.5 −15 ≧16 ± 6.0 ≧15 ± 7.8 13 ± 2.5 ^(a)Effective concentration orconcentration required to protect CEM cells against thecytopathogenicity of HIV by 50%. ^(b)Cytotoxic concentration orconcentration required to reduce CEM cell viability by 50%. * Clusterformation of the cells after 4 days incubation with the compound.

TABLE 11 Inhibitory Effect of Lectins on Giant Cell Formation BetweenHUT-78/HIV-1(III_(B)) and MOLT/4 clone 8 cells EC₅₀ (μg/ml) CompoundIndividual Values Average ABA >100 −> 100 >100 CAA >100 −> 100 >100 ConA1.7 − 9 5.4 ≧ 5.2 CPA >100 −> 100 >100 CSA >100 −> 100 >100 ECA >100 −>100 >100 EEA >4 −> 4 >4 GSA-I >100 −> 100 >100 GSA-II >100 −> 100 >100HAA >100 −> 100 >100 JAC >100 −> 100 >100 LAA >100 −> 100 >100 LBA >100−> 100 >100 LCH 45 − 45 45 LEA >100 −> 100 >100 Lotus >100 −> 100 >100MPA >100 −> 100 >100 PAA >100 −> 100 >100 PHA-L 44 − 12 − 44 33 ± 18PNA >100 −> 100 >100 PSA 45 − 58 − 58 54 ± 7.5 PTAgal >100 −> 100 >100PTAgalNac >100 −> 100 >100 SJA >100 −> 100 >100 sWGA >100 −> 100 >100TKA >100 −> 100 >100 UEA-I >100 −> 100 >100 UFA >100 −> 100 >100VVA >100 −> 100 >100 WFA >100 −> 100 >100 WGA 20 −> 4 ≧20 * Clusterformation of the cells after 1 day incubation with the compound

The invention having now been fully described, it should be understoodthat it may be embodied in other specific forms or variations withoutdeparting from its spirit or essential characteristics. Accordingly, theembodiments described above are to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

We claim:
 1. A method of preventing the transmission of one of gonorrheaand Chlamydia comprising administering to the vagina an amount of acomposition containing at least one lectin capable of binding to apathogenic microorganism or to carbohydrate moieties expressed on thevaginal epithelial cell surface, said lectin being effective to diminishthe infective capability of said microorganism, said lectin beingdispersed in a biocompatible non-toxic vehicle.
 2. The method of claim 1wherein one or more lectins are administered.
 3. The method of claim 1wherein said sexually transmissible disease is gonorrhea and said lectinis selected from the group consisting of BPA, CPA, CSA, GNA, LAA, LBA,LCH, LEA, MAA, MPA, NPA, PSA, RPA, SBA, STA, sWGA, TKA, VVA, WFA, andWGA.
 4. The method of claim 3 wherein one or more lectins areadministered.
 5. The method of claim 1 wherein said sexuallytransmissible disease is infection with Chlamydia trachomatis and saidlectin is selected from the group consisting of ABA, TKA, DSA, WFA, VFA,Jacalin, and MPA.
 6. The method of claim 5 wherein one or more lectinsare administered.
 7. The method of claim 1 wherein said vehicle isselected from the group consisting of creams, ointments, foams,suppositories, ovules, lubricants, lotions, oils, and combinationsthereof.